The present invention relates to valves. More particularly, the present invention relates to a low power type, motor-controlled magnetic valve used in controlling the gate of a water discharging pipe.
A solenoid valve is generally comprised of a solenoid coil triggered to produce a magnetic force for attracting a metal plunger or valve stem so that a valve gate can be controlled. FIGS. 1 and 2 illustrate solenoid valve used in controlling the gate of a water discharging pipe. In this structure of solenoid valve, a solenoid coil is mounted around a cylinder, and a spring is fastened inside the cylinder and stopped against a metal plunger. When electric power is connected, the solenoid valve produces a magnetic force in attract the metal plunger causing it to leave from a valve flap (See FIG. 1). When the pressure from the metal plunger is released from the valve flap, the valve flap is forced by the working fluid from a water intake pipe to open a discharging pipe, permitting the working fluid to discharge therethrough. When electric power is disconnected, the spring automatically moves the plunger back to its original position in pressing against the valve flap causing it to close the discharging pipe again. However, this solenoid valve is still not satisfactory in use. One disadvantage of this structure of solenoid valve is its high consumption of load power. Because the spring provides a force to constantly push the metal plunger downwards, the magnetic force from the solenoid coil must be strong enough to surpass the resisting force from the sping, and therefore, the required power voltage is high. Another disadvantage of this structure of solenoid valve is that the working fluid which enters the cylinder gives a resisting force to the plunger causing the solenoid coil to take longer time in attracting the metal plunger, and therefore, electric power consumption is relatively increased.